Connect the ISDN phone to the Fritzbox - how it works

If you want to use your ISDN telephone with the FritzBox, you only have to connect the devices and set up the telephone. We'll show you how.

FritzBox: Can I connect an ISDN phone?

• Not every FritzBox is suitable for working with an ISDN telephone. If there is no suitable connection, you cannot use the device.
• There are several connections on the back of the FritzBox. Search for the "FON S0" input and connect the ISDN telephone to it.
• If you want to connect several ISDN devices, your FritzBox must have a so-called S0 bus. You can use this to connect up to eight ISDN telephones to the FritzBox.

FritzBox: Setting up an ISDN telephone

1. Open the user interface of the FritzBox and log in with your password.
2. Click on the "Telephony" category on the left and then on "Telephony devices".
3. On the right side you will see the button "Set up a new device".
4. Select the option "ISDN telephone system" and follow the further instructions for the setup.

In the next practical tip, we will show you how to use your router as a repeater.

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